Muscular System Activity 4
Five muscles which are affected by the Bell's palsy on the left side of the patient's face are the following:
- Corrugator supercilii
Action: Draws the eyebrow inferiorly and wrinkles the skin of the forehead vertically - Orbicularis oculi
Action: Closes the eye - Zygomaticus major
Action: Draws the angle of the mouth superiorly and laterally (smiling) - Levator anguli oris
Action: Draws the angle of the mouth laterally and superiorly - Buccinator
Action: Presses the cheeks against the teeth and lips (whistling, blowing sucking), draws the corner of the mouth laterally, and assists in mastication by keeping the food between the teeth
Other symptoms that can be exhibited as a result of facial muscle weakness may include synkinesis, which is the involuntary contraction of a muscle even when you are trying to move a different one. It may also lead to partial or complete blindness of the eye on the affected side due to excessive dryness and scratching of the cornea since the orbicularis oculi cannot move to close the eye.